Grease compositions



United States Patent 3,281,361 GREASE COMPOSITIONS Theodore H.Kouudakjian, Berkeley, Calif., assignor to Chevron Research Company, acorporation of Delaware N0 Drawing. Filed June 30, 1964, Ser. No.379,345

6 Claims. (Cl. 252-515) The present invention relates to thickeningagents, particularly useful in forming high-temperature stable greasecompositions. More specifically, the invention relates tohigh-temperature stable grease compositions thickened with certain 1,3substituted triazenes, more particularly, triazenes formed bydiazotization of certain aminoaryl diureas.

In recent years, it has become increasingly apparent that greasecompositions must be provided that will lubricate effectively at hightemperatures; that is, at temperatures in excess of 350 F., and.particularly at ranges from 400 to 500+ F. Numerous government andindustrial grease specifications now provide that grease compositionshave minimum dropping points of 400 F. These requirements are, ingeneral, the result-s of the increased power and speed of modernautomotive equipment and aircraft. Contributing to the increasedrequirements is the expanded use of jet and turbine-type engines, whichnaturally operate at high temperatures and the increased speed of normalengine and gear train components, etc., which speeds increase thenormally encountered operating temperatures. Another factor ofimportance is the extreme pressure conditions encountered in varioustypes of modern machinery. With these increased pressures comes asignificant rise in operating temperatures.

In the lubrication art, greases having relatively high dropping pointshave been produced from salts of certain fatty acids and other organicacids. For example,'lithium salts of various fatty acids have been usedto produce high dropping point greases. However, the metallic salts tendto contribute to the compositions ions, which promote. oxidation of thelubricants themselves and additionally promote corrosion of the metallicparts being bathed in the lubricant. Further, greases with droppingpoints higher than about 450 F. have been found to be quite difficult toproduce with thickeners of this type.

The grease compositions described in this application are beneficial inthe lubrication of wearing surfaces in industrial plants wherever hightemperatures are encountered; for example, in steel mill motors andtransfer table bearings, paper mill roller bearings, etc. In heavyautomotive equipment, such as in heavy duty trucks and moving equipment,the wheel bearings become extremely hot during braking periods and thecompositions of this invention are especially suitable for lubricatingthese parts.

Greases prepared according to the present invention maintain greaseconsistencies at extremely high temperatures for long periods of time;such greases will remain unctious and not become hard or brittle attemperatures in the range of 350 F. to 500 F. These greases aresurprisingly resistant to oxidation at these elevated temperatures andwill, therefore, satisfactorily lubricate parts for long periods of timeat elevated temperatures.

In accordance with the invention, it has been discovered that hightemperature stable grease compositions are formed by the incorporationin an oil of lubricating viscosity of a 1,3bis-(hydrocarbylureyleno'hydrocarbylenoureylenoaryleno) triazene, inwhich the hydrocarbyl radicals contain a total of from 2-72 carbonatoms.

Thus, the substituted triazenes of this invention may be represented bythe general formula:

3,2813 6 1 Patented Oct. 25, 1966 ice in which R is a hydrocarbylradical of 132 carbon atoms; R is a hydrocarbylene radical of 1-32carbon atoms, and Ar is a divalent aromatic hydrocarbon radical of 6 to15 carbon atoms.

The substituted triazenes of this invention may be formed by the diazocoupling of two moles of an amino,- diurea. Thus, the aminodiureas whichare coupled may be dissimilar; however, the compounds may most easily beprepared by the simultaneous diazotization and coupling of theaminodiurea and thus the units would ordinarily be similar. On the otherhand, a portion of one aminodiurea may be diazotized and coupled with anequimolar portion of another aminodiurea.

Suitable aminodiurea intermediates may be prepared by reacting one moleof a diisocyanate with one mole of a primary or secondary monoamine andone mole of an aromatic polyamine.

Examples of suitable monomines include the following: primary amines,such as methylamine, dimethylamine, isoamylamine,methyl-Z-ethylhexylarnine, aniline, diphenylamine, octadecylamine,naphthylamine, cyclohexylmethylamine, butylamine; secondary amines, suchas piperidine, dimethylamine, diisopropylamine, di-n-butylamine,diethylamine.

R in the formula, which is derived from the diisocyanate, ishydrocarbylene and may be either alkylene or arylene. The radicals maybe substituted radicals containing various reactive substituents, suchas hydroxy, carboxy, halo, nitro, etc. Examples of suitable aromaticradicals include orthophenylene, meta-phenylene, paraphenylene,tolylene, dimethyl phenylene, naphthylene, methylene-bis-phenyl, andbiphenylene, etc. Examples of suitable alkylene radicals includeethylene, trimethylene, tetramethylene, and branch chain alkyleneradicals, such as isopropylene, etc.

Suitable aryldiamines from which Ar in the formula is derivedincludebenzidene, ortho, meta, para phenylene diamines,diaminonap-hthalenes, such as 1,2- 1,4-, 1,5-, 1,6-, 2,3-, and2,6-naphthalene diamines.

The aminodiureas may be prepared separately; may be prepared in an inertsolvent, which is then evaporated;,

or, more preferably, they may be prepared in situ. Preparation in situcomprises mixing the amines and the isocyanates together, utilizing as asolvent a portion of the oil that is to serve as the lubricant base,heating the mixture in a reaction vessel at temperatures from about 70F. to 600 F. for a time sufficient to cause formation of theintermediate aminodiureas.

The following reaction illustrates the preparation of the aminodiureacompounds:

Minor amounts of other materials will be formed. However, the principalproduct will be the aminodiurea illustrated by the above formula.Examples of the other compounds which will be formed in small quantitiesare a diurea, which results from the reaction of two molecules ofthemonamine with one of the diisocyanate and longer polymeric compoundswhich result from reaction of more than one mole of the diamine with thediisocy-anate.

The following examples illustrate the preparation of the aminodiureaintermediates. The examples are merely illustrative and not limiting.

Example 1 Preparation of amin0diurea.-2l.6 gm. (0.20 mole) ofmeta-phenylenediamine, 60.0 gm. (0.20 mole) of tallow amine(octadecylamine) and ten gm. of an octylated diphenylamine oxidationinhibitor were heated together over a steam plate until the mixturebecame liquid. The melt was then added to 34.8 gms. of an 80:20

In order to demonstrate the surprising effectiveness of the greasecompositions of this invention in preventing wear and oxidation at hightemperatures, a thin film oxidation test and a high-speed ball bearingtest isomeric mixture of 2,4-, 2,6-toluene diisocyanate in 450 5 wereemployed. gm. of a paraflinic oil having a viscosity of 480 SSU The thinfilm test measured the ability of the grease at 100 F. This mixture wasstirred in a high-speed compositions to maintain grease-likecharacteristics, parblender and a grease formed immediately. The greaseticularly, the retention of pliability and resistence to oxiwas thentransferred to a beaker and hand-stirred until dation under exposure ofa thin film of grease to high evolution of heat ceased. The grease wasthen milled temperatures. The test also indicated other grease charin athree-roll mill, transferred to a shallow metal pan acteristics, such astendency to bleed, flake and become and heated at 340 F. for 1% hours.The grease was tacky. The thin film test was run as follows: stirredwhile being heated. It was then cooled and to The grease to be testedwas coated on a metal strip, a 482 gm. portion an additional 150 gm.portion of oil the grease coating being of uniform dimensions: ,4 wasadded; the mixture was hand-mixed and milled on 15 thick, A; wide, and 2/2" long. This grease sample a three-roll mill. The resulting productwas a thick, was placed in an oven maintained at 350 F. and obsmooth,chocolate-brown grease containing 14.5% by served at periodic intervalsuntil the sample no longer weight of the thickener and about 1.5% byweight of existed as a grease. The life of the grease was the theantioxidant. number of hours during which the grease could be so Aspreviously mentioned, the aminodiureas, as preheated before it lost itsgrease-like characteristics, that pared in Example 1, are diazotized andcoupled. The is, the time at which the test sample became hard andcoupling reaction may be carried out in basic, neutral brittle. orweakly acidic solution. An amount of nitrous acid, The bearing life fora particular grease composition or in this case, sodium nitrite,sufiicient to diazotize onewas determined by the following testprocedure, which half of the aminodiurea is added. Then the addition isknown as the Navy high-speed bearing test, as deof a weak acid, such asacetic acid, accomplishes the scribed in Federal Test Method 331.1. Inthis test, a coupling reaction. This procedure is illustrated by theball bearing was operated at 10,000 r.p.m. continuously followingexample: for approximately twenty-two hours at a temperature Example 2of 350 F. The apparatus was then cooled to room p temperature during aperiod of two hours. The pro- W W?" of f f (0029 mole) of cedure ofoperation at 10,000 r.p.m. at the noted temsodlun} mtnte was mlxed Intoa base grease Prepared perature and cooling was repeated until there wasbearaccording to the procedure of Example 1. The base ing failure.grease contams 9 anlmodlurea- The following table compiled results ofthe above- (Q- 111016) glaclal acetlc added Slowly mentioned testperformed on a grease composition prewrth thorough stirring. The greasebecame yellow, then pared according to Example 2, using as a base lubriafter about two hours of f It became orange m cant, a Californiaparafiinic neutral oil having a viscolor. The grease was heated in anoven for three hours cosity of 480 SSU at The grease contained at wlthoccaslonal Snmng the odor of 10.2% of the triazene thickener and 1.0%dioctylated acct: alcld w no longer l l The grease was 40 diphenylamineoxidation-inhibitor. For purposes of comthel} milled three'rou mm F Q P'The parison, data from a grease containing 10.8% of an sultmg mammal hadan ASTM droppmg Pomt of 500 aminodiurea prepared according to Example 1and 1.4% P0230 P6029 4 and a deep colon of the same oxidation inhibitoris included.

The following table summarizes data obtained by preparing greasesfollowing the general procedures of Ex- TABLE H amples l and 2, varyingthe ratios of acetic acid and sodium nitrite to the diurea. The dataincluded are the Thin Film Hlgh Speed g 'g%} at ASTM UnworkedPenetration (P ASTM Worked Thickener Grease Life Penetration (P ASTMDropping Point (DP), the Bemng I Bearmgn Avemge molar equivalents ofsodium mtnte and acetic acid to Life, LifeJlIS- Life two moles of totalaminodiurea and the percent thickener in the grease. Trtazene 70s 433483 460 The following aminodiureas were coupled: Ammodmma 380 A.Aminodiurea prepared according to Example 1. B Animodiu ea preparedaccording to Example 1 sub- The data in the above table demonstrate theexcelit ti h 1 di ili as h di i lent oxidation resistance and high-speedlubrication characteristics of the grease compositions of this inven-The fouowmg base 0115 employed tion. Mineral oil based greases aregenerally unsuit- C. California parafiinic base neutral oil having avisable for prolonged use at temperatures above 300 F.;

cosity of 480 SSU at 100 F. greases formulated for use under theseconditions ordi- D. Methyl phenyl silicone oil having a viscosity of 500narily require synthetic ester based oils. Thus, the subcentistokes at25 C. stituted triazene thickeners of this invention allow an TABLE IMoi. Eq., M01. Eq., Mole Ratio, Percent Unworked Worked GreaseAmlnodiurea Base 011 NaNO; HOAe NBNOz/ Thiekener ASTM DP Penetration,Penetration,

HOAc P0 Pro 1 A c 1. 00 1. 00 1. 0 10. 2 460 247 283 2 A.-- c- 0. 50 1.00 0. 5 14. 6 518 277 360 a A c 1. 00 1. 00 1. 0 14. 6 500 241 307 4 A o2.00 1.00 h 2.0 14.6 522 230 204 5 A o- 2. 00 0. 75 2. 7 11. 9 500 232281 a A 0-..--- 2. 00 0. 50 4. 0 11.2 500 236 297 7 A O 1. 00 0.25 4. 010.6 508 231 288 s A D 1. 00 0. 50 2. 0 31. 8 502 276 306 0 B C- 0. 0.50 1. 4 16. 6 460 218 203 important advance in enabling mineral oilbased greases to perform adequately at high temperatures and speeds.

Lubricating oils which can be employed as base oils in the greasecompositions of this invention include a wide variety of oils, such asnaphthenic-based, parafiinbased, and mixed-base mineral lubricatingoils. Other hydrocarbon lubricants, e.g., lubricating oils derived fromcoal products, and synthetic oils, e.g., alkylene polymers (such aspolymers of propylene, butylene, etc., and mixtures thereof), alkyleneoxide-type polymers (e.g., alkylene oxide polymers prepared bypolymerizing the alkylene oxide, e.g., propylene oxide, etc., in thepresence of water, or alcohols, e.g., ethyl alcohol), carboxylic acidesters (e.g., those which are prepared by esterifying such carboxylicacids as adipic acid, azelaic acid, suberic acid, sebacic acid, alkenylsuccinic acid, fumaric acid, maleic acid, hexanoic acid, etc., withalcohols, such as butyl alcohol, heXyl alcohol, 2-ethy1 hexyl alcohol,dodecyl alcohol, pentaerythritol, etc.). Other suitable base oils areliquid esters of acids of phosphorus, alkyl benzenes, polyphenyls (e.g.,biphenyls and terphenyls), alkyl biphenyl ethers, etc. Especiallysuitable for high temperature use are the polymers of silicon; such astetraethyl silicate, hexa (4-methyl-2- pentoxy) disiloxane,tetraisopropyl silicate, hexa(4- methyl-2-pentoXy)-disiloxane,polymethyl siloXane, and polymethyl phenyl siloxane, etc. The base oilsmay also comprise mixtures of the aforementioned minerals and syntheticoils.

The grease compositions of this invention contain thesubstituted-triazene thickeners in amounts sufi'lcient to thicken theoils to the consistency of greases. In general, in amounts of from 5 to50% by Weight are suiticient; amounts of from to 30% by weight arepreferred.

In addition to the thickening agents heretofore described, the greasecompositions may contain other grease-thickening agents, oxidationinhibitors, viscosity improving agents, dyes, etc.

While in the presentation of this invention numerous examples have beengiven and the invention described with respect to certain embodiments,it is not so limited, and it is to be understood that variations andmodifications which are obvious to those skilled in the art may be madewithout departing from the scope or the spirit of the invention, whichis only to be limited by the appended claims.

I claim:

1. A grease composition comprising an oil of lubricating viscosity and,in an amount sufiicient to thicken said oil to the consistency of agrease, a substituted triazene compound of the general formula:

wherein R is selected from the group consisting of hydrocarbyl radicalsof 2 to 32 carbon atoms, R is a hydrocarbylene radical of 1 to 32 carbonatoms, and Ar is a divalent aromatic hydrocarbon radical of 6 to 15carbon atoms.

2. The grease composition of claim 1 wherein the triazene is present inan amount of from 5 to by R NHCONHR NHCONHArN =N-NHArNHCONHR -NHCONHRwherein R is selected from the group consisting of hydrocarbyl radicalsof 1 to 32 carbon atoms, R is a hydrocarbylene radical of 1 to 32 carbonatoms, and

Ar is a divalent aromatic hydrocarbon radical of 6 to 15 carbon atoms.

References Cited by the Examiner UNITED STATES PATENTS 2,710,841 6/1955Swakon et al. 2525l.5

DANIEL E. WYMAN, Primary Examiner.

IRVING VAUGHN, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No a 3,281, 361 October 25, 1966 Theodore H. Koundakjian It is hereby certifiedthat error appears in the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below.

Column 5, line 27, for "ploymethyl phenyl siloxane" readpolymethylphenyl siloxane column 6, line 11, for "Z to 32" read 1 to 32Signed and sealed this 5th day of September 1967 (SEAL) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner ofPatents

1. A GREASE COMPOSITION COMPRISING AN OIL OF LUBRICANT VISCOSITY AND, INAN AMOUNT SUFFICIENT TO THICKEN SAID OIL TO THE CONSISTENCY OF A GREASE,A SUBSTITUTED TRIAZENE COMPOUND OF THE GENERAL FORMULA: